U.S. patent number 7,396,086 [Application Number 11/695,672] was granted by the patent office on 2008-07-08 for press-fit pick.
Invention is credited to Ronald Crockett, David R. Hall, Jeff Jepson.
United States Patent |
7,396,086 |
Hall , et al. |
July 8, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
Press-fit pick
Abstract
In one aspect of the invention, a pick comprises a shank
attached to a base of a steel body, a cemented metal carbide core
press fit into the steel body opposite the shank, and an impact tip
bonded to a first end of the core opposite the shank. The impact
tip comprises a superhard material opposite the core, and the core
comprises a second end and a largest diameter. A distance through
the body from the shank to the second end of the core is less than
the largest diameter of the core.
Inventors: |
Hall; David R. (Provo, UT),
Crockett; Ronald (Provo, UT), Jepson; Jeff (Provo,
UT) |
Family
ID: |
39589525 |
Appl.
No.: |
11/695,672 |
Filed: |
April 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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11686831 |
Mar 15, 2007 |
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Current U.S.
Class: |
299/113;
299/111 |
Current CPC
Class: |
E21C
35/183 (20130101); E21C 35/1831 (20200501) |
Current International
Class: |
E21C
35/18 (20060101) |
Field of
Search: |
;299/111,113,105,104 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kreck; John
Attorney, Agent or Firm: Wilde; Tyson J.
Parent Case Text
CROSS REFERENCES
This patent application is a continuation-in-part of U.S. patent
application Ser. No. 11/686,831 filed on Mar. 15, 2007 and entitled
A Superhard Composite Material Bonded to a Steel Body, which is
herein incorporated by reference in its entirety.
Claims
What is claimed is:
1. A pick, comprising: a shank attached to a base of a steel body;
a cemented metal carbide core press fit into the steel body
opposite the shank; an impact tip bonded to a first end of the core
opposite the shank; the impact tip comprising a carbide substrate
and a diamond material bonded to the substrate at a non-planar
interface opposite the shank, the substrate comprising a thickness
less than 6 mm; the core comprising a second end and a largest
diameter; and wherein a distance through the body from the shank to
the second end of the core is less than the largest diameter of the
core.
2. The pick of claim 1, wherein the shank, carbide core and diamond
material are generally coaxial.
3. The pick of claim 1, wherein the diamond material comprises
polycrystalline diamond, refractory metal bonded diamond, silicon
bonded diamond, layered diamond, infiltrated diamond, thermally
stable diamond, natural diamond, vapor deposited diamond,
physically deposited diamond, diamond impregnated matrix, diamond
impregnated carbide, chromium, titanium, aluminum, tungsten, or
combinations thereof.
4. The pick of claim 1, wherein the largest diameter of the core is
between 0.25 and 2 inch.
5. The pick of claim 1, wherein the cemented metal carbide core and
the impact tip are brazed together with a braze comprising a
melting temperature from 700 to 1200 degrees Celsius.
6. The pick of claim 1, wherein an impact surface of the impact tip
comprises a conical geometry, semispherical geometry, domed
geometry, flat geometry or combinations thereof.
7. The pick of claim 1, wherein at least a portion of the steel
body comprises a generally frustoconical geometry when manufactured
or when in use.
8. The pick of claim 1, wherein the steel body comprises a tapered
portion.
9. The pick of claim 1, wherein the steel body comprises a wear
resistant material disposed on at least a portion of an exposed
surface of the body.
10. The pick of claim 1, wherein the shank comprises a coating of
wear resistant material.
11. The pick of claim 1, wherein a reentrant is formed at the
intersection of the shank and the base of the steel body.
12. The pick of claim 1, wherein the steel body is stepped.
13. The pick of claim 1, wherein the press fit comprises an
interference of between 1 and 5 thousandth of an inch proximate the
second end of the core.
14. A pick, comprising: a shank attached to a base of a steel body;
a core harder than the steel body being press fit into the steel
body opposite the shank; an impact tip comprising a carbide
substrate and a diamond material bonded to the substrate at a
non-planar interface is bonded to a first end of the core opposite
the shank; and a second end of the core is press fit deeper into
the steel body than a width of the core, wherein the substrate
comprising a thickness less than 6 mm.
15. The pick of claim 14, wherein the diamond material comprises an
apex with a 0.050 to 0.200 inches radius.
16. A pick, comprising: a shank attached to a base of a steel body;
a cemented metal carbide core press fit into the steel body
opposite the shank; an impact tip bonded to a first end of the core
opposite the shank; and the impact tip comprising a carbide
substrate and a diamond material bonded to the substrate at a
non-planar interference opposite the shank, wherein the substrate
comprising a thickness less than 6 mm and the diamond material
comprising a thickness greater than 100 inches.
17. The tool of claim 16, wherein a volume of the diamond material
is 75 to 150 percent of a volume of the carbide substrate.
18. The tool of claim 16, wherein the diamond material comprises a
substantially conical surface with a side which forms a 35 to 55
degree angle with a central axis of the impact tip.
19. The pick of claim 16, wherein the diamond material comprises an
apex with a 0.050 to 0.200 inches radius and is over 100 inches
thick.
Description
BACKGROUND OF THE INVENTION
Efficient degradation of materials is important to a variety of
industries including the asphalt, mining, construction, drilling,
and excavation industries. In the asphalt industry, pavement may be
degraded using picks, and in the mining industry, picks may be used
to break minerals and rocks. Picks may also be used when excavating
large amounts of hard materials. In asphalt recycling, a drum
supporting an array of picks may rotate such that the picks engage
a paved surface causing it to break up. Examples of degradation
assemblies from the prior art are disclosed in U.S. Pat. No.
6,824,225 to Stiffler, US Pub. No. 20050173966 to Mouthaan U.S.
Pat. No. 6,692,083 to Latham, U.S. Pat. No. 6,786,557 to
Montgomery, Jr., U.S. Pat. No. 3,830,321 to McKenry et at, US. Pub.
No. 20030230926, U.S. Pat. No. 4,932,723 to Mills, US Pub. No.
20020175555 to Merceir, U.S. Pat. No. 6,854,810 to Montgomery, Jr.,
U.S. Pat. No. 6,851,758 to Beach, which are all herein incorporated
by reference for all they contain.
The picks typically have a tungsten carbide tip, which may last
less than a day in hard milling operations. Consequently, many
efforts have been made to extend the life of these picks. Examples
of such efforts are disclosed in U.S. Pat. No. 4,944,559 to Sionnet
et al., U.S. Pat. No. 5,837,071 to Andersson et at, U.S. Pat. No.
5,417,475 to Graham et al., U.S. Pat. No. 6,051,079 to Andersson et
al., and U.S. Pat. No. 4,725,098 to Beach, U.S. Pat. No. 6,733,087
to Hall et al., U.S. Pat. No. 4,923,511 to Krizan et al., U.S. Pat.
No. 5,174,374 to Hailey, and U.S. Pat. No. 6,868,848 to Boland et
al., all of which are herein incorporated by reference for all that
they disclose.
BRIEF SUMMARY OF THE INVENTION
In one aspect of the invention, a pick comprises a shank attached
to a base of a steel body, a cemented metal carbide core press fit
into the steel body opposite the shank, and an impact tip bonded to
a first end of the core opposite the shank. The impact tip
comprises a superhard material opposite the core, and the core
comprises a second end and a largest diameter. A distance through
the body from the shank to the second end of the core is less than
the largest diameter of the core. The shank, carbide core and
superhard material may be generally coaxial. The press fit may
comprise an interference of between 1 and 5 thousandths of an inch
proximate the second end of the core.
The largest diameter of the core may be between 0.25 and 2 inch.
The cemented metal carbide core may comprise a volume of 0.250
cubic inches to 6.00 cubic inches. The cemented metal carbide core
and the impact tip may be brazed together with a braze material
comprising a melting temperature from 700 to 1200 degrees Celsius.
An impact surface of the impact tip may comprise a conical
geometry, semispherical geometry, domed geometry, flat geometry, or
combinations thereof.
The superhard material may comprise diamond, polycrystalline
diamond, cubic boron nitride, refractory metal bonded diamond,
silicon bonded diamond, layered diamond, infiltrated diamond,
thermally stable diamond, natural diamond, vapor deposited diamond,
physically deposited diamond, diamond impregnated matrix, diamond
impregnated carbide, cemented metal carbide, chromium, titanium,
aluminum, tungsten, or combinations thereof.
The steel body may comprise a tapered portion. A least a portion of
the steel body may comprise a generally frustoconical geometry when
manufactured or when in use. The steel body may be stepped. The
steel body may comprise a wear resistant material disposed on at
least a portion of an otherwise exposed surface of the body. The
steel body may comprise a volume of 0.5 cubic inches to 25 cubic
inches.
The shank may comprise a coating of wear resistant material. A
reentrant may be formed at the intersection of the shank and the
base of the steel body. The shank may be secured within a holder
attached to a milling drum connected to the underside of a pavement
milling machine. The shank may be secured to a bit body adapted for
subterranean drilling, coal mining, or a trenching machine.
In another aspect of the invention, a pick comprises a shank
attached to a base of a steel body. The steel body comprises a base
diameter encompassing a rear steel volume proximate the shank, and
a forward steel volume proximate to the rear volume opposite the
shank that is encompassed by at least one diameter smaller than the
base diameter. A carbide core is press fit into the steel body
opposite the shank and is bonded to an impact tip comprising a
superhard material opposite the core. The core comprises a forward
core volume and a rear core volume respectively proximate the
forward and rear steel volumes. A ratio of the forward core volume
to the forward steel volume is less than 3.5 times a ratio of the
rear core volume to the rear steel volume.
In another aspect of the invention, a pick comprises a shank
attached to a base of a steel body. A core harder than the steel is
press fit into the steel body opposite the shank. An impact tip is
bonded to a first end of the core opposite the shank and comprises
a superhard material opposite the core. A second end of the core is
press fit deeper into the steel body than a width of the core.
In one aspect of the invention, a high impact resistant tool has a
superhard material bonded to a cemented metal carbide substrate at
a non-planar interface. At the interface, the substrate has a
tapered surface starting from a cylindrical rim of the substrate
and ending at an elevated flatted central region formed in the
substrate. The superhard material has a pointed geometry with a
sharp apex having 0.050 to 0.125 inch radius. The superhard
material also has a 0.100 to 0.500 inch thickness from the apex to
the flatted central region of the substrate. In other embodiments,
the substrate may have a non-planar interface. The interface may
comprise a slight convex geometry or a portion of the substrate may
be slightly concave at the interface. A volume of the superhard
material may be 75 to 150 percent of a volume of the carbide
substrate. In some embodiments, the volume of diamond may be up to
twice as much as the volume of the carbide substrate. The
substantially pointed geometry may comprise a side which forms a 35
to 55 degree angle with a central axis of the tool. The angle may
be substantially 45 degrees. The substantially pointed geometry may
comprise a convex and/or a concave side. In some embodiments, the
radius may be 0.090 to 0.110 inches. Also in some embodiments, the
thickness from the apex to the non-planar interface may be 0.125 to
0.275 inches. The substrate may comprise a height of 2 to 6 mm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of an embodiment of a plurality
of picks on a rotating drum attached to a motor vehicle.
FIG. 2 is an orthogonal diagram of an embodiment of a pick.
FIG. 3 is a cross-sectional diagram of an embodiment of a pick.
FIG. 4 is an exploded diagram of an embodiment of a pick.
FIG. 5 is a cross-sectional diagram of another embodiment of a
pick.
FIG. 6 is a cross-sectional diagram of another embodiment of a
pick.
FIG. 7 is a cross-sectional diagram of another embodiment of a
pick.
FIG. 8 is an orthogonal diagram of another embodiment of a
pick.
FIG. 9 is an orthogonal diagram of another embodiment of a
pick.
FIG. 10 is a perspective diagram of an embodiment of a pick.
FIG. 11 is an orthogonal diagram of an embodiment of a drill
bit.
FIG. 12 is an orthogonal diagram of another embodiment of a drill
bit.
FIG. 13 is a perspective diagram of an embodiment of a
trencher.
FIG. 14 is an orthogonal diagram of another embodiment of a
trencher.
FIG. 15 is a flowchart illustrating an embodiment of a method for
providing cost effective picks.
FIG. 16 is a flowchart illustrating another embodiment of a method
for providing cost effective picks.
DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED
EMBODIMENT
FIG. 1 is a cross-sectional diagram of an embodiment of a plurality
of picks 101 attached to a rotating drum 102 connected to the
underside of a pavement recycling machine 103. The recycling
machine 103 may be a cold planer used to degrade man-made
formations such as pavement 104 prior to the placement of a new
layer of pavement. Picks 101 may be attached to the drum 102
bringing the picks 101 into engagement with the formation. A holder
105 or block is attached to the rotating drum 102, and the pick 101
is inserted into the holder 105. The holder 105 or block may hold
the pick 101 at an angle offset from the direction of rotation,
such that the pick 101 engages the pavement at a preferential
angle.
FIG. 2 is an orthogonal diagram of an embodiment of a pick 101. The
pick 101 comprises a steel body 201 attached to a shank 202 at a
steel base 203 of the body 201. The steel body 201 may comprise
steel selected from the group consisting of 4140, ENB10, S7, S5,
A2, tool steel, hardened steel, alloy steels, PM M-4, T-15, M-4,
M-2, D-7, D-2, Vertex, PM A-11, A-10, A-6, O-6, O-1, H-13, EN30B,
and combinations thereof. A cemented metal carbide core 204 is
press fit into the steel body 201 opposite the shank 202. The steel
body 201 may comprise a length 210 from a distal end to the steel
base 203. In some embodiments of the invention the carbide core 204
may be press fit into at least 65% of the length 210 of the steel
body 201. An impact tip 205 is bonded to a first end 206 of the
core 204 opposite the shank 202. The impact tip 205 comprises a
superhard material 207 opposite the core 204.
The superhard material 207 may comprise diamond, polycrystalline
diamond with a binder concentration of 1 to 40 weight percent,
cubic boron nitride, refractory metal bonded diamond, silicon
bonded diamond, layered diamond, infiltrated diamond, thermally
stable diamond, natural diamond, vapor deposited diamond,
physically deposited diamond, diamond impregnated matrix, diamond
impregnated carbide, monolithic diamond, polished diamond, course
diamond, fine diamond, non-metal catalyzed diamond, cemented metal
carbide, chromium, titanium, aluminum, tungsten, or combinations
thereof. The superhard material 207 may be a polycrystalline
structure with an average grain size of 10 to 100 microns. Picks
101 often rotate within their holders 105 or blocks upon impact
with the pavement which allows wear to occur evenly around the pick
101. The impact tip 205 may be angled to cause the pick 101 to
rotate within the bore of the holder 105. A protective spring
sleeve 208 may be disposed around the shank 202 both for protection
and to allow the high impact resistant pick 101 to be press fit
into a holder 105 while still allowing the pick to rotate. A washer
209 may also be disposed around the shank 202 such that when the
pick 101 is inserted into the holder 105, the washer 209 protects
an upper surface of the holder 105 and in some cases facilitates
rotation of the pick 101.
Referring now to FIG. 3, the core 204 of the pick 101 comprises a
second end 301 and a diameter 302. Once the core 204 is press fit
into the body 201, a distance 303 through the body from the shank
202 to the second end 301 of the core 204 is less than the diameter
302. The diameter 302 may be between 0.25 and 2 inch. It is
believed that by press fitting the core 204 into the body 201 such
that the second end 301 is closer to the shank 202 than the width
of the diameter 302 of the core 204, that the ratio of core
diameter 302 to press fit depth 304 is optimized for wear life of
the pick 101. At least a portion of the body 201 may comprise a
generally frustoconical geometry when manufactured or when in
use.
The superhard material 207 may be at least 4,000 HK and in some
embodiments it may be 1 to 20000 microns thick. In embodiments,
where the superhard material is a ceramic, the material may
comprise a region, preferably near its surface, that is free of
binder material. Infiltrated diamond is typical made by sintering
the superhard material 207 adjacent a cemented metal carbide
substrate 305 and allowing a metal (such as cobalt) to infiltrate
into the superhard material 207. As disclosed in FIG. 3 the impact
tip 205 may comprise a carbide substrate 305 bonded to the
superhard material 207. In some embodiments the impact tip 205 may
be connected to the core 204 before the core is press fit into the
body 201. Typically the substrate of the impact tip 205 is brazed
to the core 204 at a planar interface 306. The tip 205 and the core
204 may be brazed together with a braze comprising a melting
temperature from 700 to 1200 degrees Celsius.
The superhard material 207 may be bonded to the carbide substrate
305 through a high temperature high pressure process. During high
temperature high pressure (HTHP) processing, some of the cobalt may
infiltrate into the superhard material such that the substrate 305
comprises a slightly lower cobalt concentration than before the
HTHP process. The superhard material 207 may preferably comprise a
1 to 5 percent cobalt concentration by weight after the cobalt or
other binder infiltrates the superhard material 207. The superhard
material 207 may also comprise a 1 to 5 percent concentration of
tantalum by weight. Other binders that may be used with the present
invention include iron, cobalt, nickel, silicon, carbonates,
hydroxide, hydride, hydrate, phosphorus-oxide, phosphoric acid,
carbonate, lanthanide, actinide, phosphate hydrate, hydrogen
phosphate, phosphorus carbonate, alkali metals, ruthenium, rhodium,
niobium, palladium, chromium, molybdenum, manganese, tantalum or
combinations thereof. In some embodiments, the binder is added
directly to the superhard material's mixture before the HTHP
processing and do not rely on the binder migrating from the
substrate into the mixture during the HTHP processing.
The superhard material 207 may comprise a substantially pointed
geometry with a sharp apex comprising a radius of 0.050 to 0.200
inches. In some embodiments, the radius is 0.090 to 0.110 inches.
It is believed that the apex may be adapted to distribute impact
forces, which may help to prevent the superhard material 207 from
chipping or breaking. The superhard material 207 may comprise a
thickness of 0.100 to 0.500 inches from the apex to the interface
with the substrate 305, preferably from 0.125 to 0.275 inches. The
superhard material 207 and the substrate 305 may comprise a total
thickness of 0.200 to 0.700 inches from the apex to the core 204.
The sharp apex may allow the high impact resistant pick 101 to more
easily cleave asphalt, rock, or other formations.
A radius 307 on the second end 301 of the core 204 may comprise a
smaller diameter than the largest diameter 302. A reentrant 308 may
be formed on the shank 202 near and/or at an intersection 309 of
the shank 202 and the base 203 of the body 201. It is believed that
placing the reentrant 308 near the intersection 309 may relieve
strain on the intersection 309 caused by impact forces.
Referring now to FIG. 4, the shank 202 may be coated with a hard
surface 401. The hard surface 401 may comprise a cemented metal
carbide, chromium, manganese, nickel, titanium, silicon, hard
surfacing, diamond, cubic boron nitride, polycrystalline diamond,
diamond impregnated carbide, diamond impregnated matrix, silicon
bonded diamond, deposited diamond, aluminum oxide, zircon, silicon
carbide, whisker reinforced ceramics, nitride, stellite, or
combinations thereof. The hard surface 401 may be bonded to the
shank 202 though the processes of electroplating, cladding,
electroless plating, thermal spraying, annealing, hard facing,
applying high pressure, hot dipping, brazing, or combinations
thereof. The hard surface 401 may comprise a thickness of 0.001 to
0.200 inches. The hard surface 401 may be polished.
The carbide core 204 may be press fit into the steel body 201 with
an interference of between 1 and 5 thousandths of an inch. A base
diameter 402 of the core 204 may be between 1 and 5 thousandths of
an inch larger than a cavity diameter 403 of a cavity 404 in the
steel body 201 into which the core 204 is press fit.
An impact surface 405 of the impact tip 205 may comprise a conical
geometry, semispherical geometry, domed geometry, flat geometry, or
combinations thereof. The impact tip 205 may comprise a generally
circular shape, a generally annular shape, a generally spherical
shape, a generally pyramidal shape, a generally conical shape, a
generally arcuate shape, a generally asymmetric shape, or
combinations thereof.
Referring now to FIG. 5, a cross-sectional diagram discloses an
embodiment of the invention in which a ratio of forward core volume
512 to forward steel body volume 505 is less than 3.5 times a ratio
of rear core volume 511 to rear steel body volume 504. The steel
body 201 comprises a base diameter 501, and a total body volume
determined by a variable body diameter 502 along a body length 503.
The steel body may comprise a total body volume of 0.5 inches to 25
cubic inches. The total body volume comprises a rear body volume
504 proximate the shank 202 and a forward body volume 505 proximate
the rear volume 504 and opposite the shank 202. The forward body
volume 505 encompasses at least one variable body diameter 502 that
is smaller than the base diameter 501. Aboundary 510 between the
forward and rear body volumes 505, 504 may be disposed at the first
variable body diameter 502 that is smaller than the base diameter
501 in the direction moving from the shank 202 towards the impact
tip 205 in embodiments where the shank 202, carbide core 204, and
superhard material 207 are generally coaxial. The rear body volume
504 may be disposed within a rear volume distance 506 from the
steel base 203 of the body 201. The forward body volume may be
disposed in a forward volume distance 507 between the rear volume
distance 506 and a distal end of the total body length 503. A
carbide core 204 is press fit into the steel body 201 opposite the
shank 202 and is bonded to an impact tip 205. The impact tip 205
comprises a superhard material 207 opposite the core 204. The core
204 comprises a total volume determined by a variable core diameter
508 along a total core length 509. The core 204 may comprise a
total volume of 0.250 cubic inches to 6.00 cubic inches. The core
204 comprises a rear core volume 511 determined by the amount of
the total core volume disposed within the rear volume distance 506
from the steel base 203. The core 204 also comprises a forward core
volume 512 determined by the amount of the total core volume
disposed within the forward volume distance 507. The rear and
forward core volumes 511, 512 are respectively proximate the rear
and forward steel volumes 504, 505. A ratio of the forward core
volume 512 divided by forward steel volume 505 is less than 3.5
times a ratio of the rear core volume 511 divided by rear steel
volume 504. The relationship of these ratios is believed to press
fit the core 204 into a sufficient press fit depth 304 and into a
sufficient amount of steel body 201 in order to optimize the wear
life of the pick 101. In some embodiments of the invention the pick
101 may comprise a ratio of total core volume to total steel body
volume of between 12 and 35%.
In FIG. 6 an embodiment of the invention is disclosed in which the
pick 101 comprises a stepped steel body 601. It is believed that in
some applications a stepped body 601 may help to maximize the
amount of steel surrounding the press fit core 204 without
maximizing the bulkiness of the body 201. FIG. 6 also discloses a
generally non-planar interface 602 between the carbide substrate
305 and the superhard material 207 on the impact tip 205.
Referring now to FIG. 7, an embodiment of the invention is shown in
which the central axes of the carbide core 204 and the steel body
201 are not coaxial. In the present embodiment an acute
intermediate angle 703 is shown between the two axes 701, 702. The
intermediate angle 703 may be acute, obtuse, or perpendicular.
Although in the present embodiment the impact tip 205 is coaxial
with the carbide core 204, in some embodiments of the invention the
impact tip 205 may not be coaxial with the core 204.
FIGS. 8 through 10 disclose embodiments of picks 101 in which at
least part of an exposed surface 801 of the steel body 201
comprises a wear resistant material. The present invention may be
compatible for attaching a wear resistant material to the steel
body 201 through a heating process. Heating may alter the bond
between the diamond and carbide substrate leaving residual
stresses. The stresses may be avoided by press fitting the core
into the steel body subsequent the heating process.
Referring now to FIG. 8, the pick 101 comprises wear resistant
inserts 802 on the exposed surface 801 of the steel body 201. The
inserts may comprise a cemented metal carbide, hardened steel,
diamond, metal, or combinations thereof. Referring now to FIG. 9, a
wear resistant coating 901 may be disposed on the exposed surface
801 of the steel body 201. The coating may comprise a hard material
selected from the group consisting of cemented metal carbide,
chromium, manganese, nickel, titanium, silicon, hard surfacing,
diamond, cubic boron nitride, polycrystalline diamond, diamond
impregnated carbide, diamond impregnated matrix, silicon bonded
diamond, deposited diamond, aluminum oxide, zircon, silicon
carbide, whisker reinforced ceramics, nitride, stellite, or
combinations thereof. The coating 901 may be bonded to the exposed
surface 801 though the processes of electroplating, cladding,
electroless plating, thermal spraying, annealing, hard facing,
applying high pressure, hot dipping, brazing, or combinations
thereof. The coating 901 may comprise a thickness of 0.001 to 0.200
inches.
Referring now to FIG. 10, a pick 101 is shown in which a composite
material 1001 is disposed in concentric annular deposits on the
exposed surface 801 of the steel body 201 to protect the body 201
from wear. The composite material 1001 may comprise a plurality of
diamond, diamond-like and/or cubic boron nitride particles held
within a matrix. The matrix may comprise 40 to 80 percent diamond
or cubic boron nitride particles by volume. It is believed that
that too low of a particle concentration causes the matrix around
the particles to wear away thereby causing more of the particles to
be exposed and thereby fall out, which in turn exposes new
particles. Preferably there is a high enough concentration of the
particles that the particles protect the matrix from wearing away
and effectively form a super wear resistant composite material. The
particles may comprise an average particle size of between 1 and
3500 microns. More preferably, the average particle size is less
than 50 microns. Most preferably, the average particle size is less
than 10 microns. It is believed the smaller the particle size the
greater wear resistance that the composite material will have and
thereby protect the steel from wear.
The matrix material may be a metal or a resin bonded. Metal bonded
particles may be bonded by a matrix comprising of silver, copper,
silicon, indium, nickel, manganese, palladium, zinc, cobalt,
titanium, tin, gold, boron, chromium, germanium, aluminum, iron,
gallium, vanadium, phosphorus, molybdenum, platinum, alloys,
mixtures and combinations thereof. In some embodiments, the
superhard particles may be coated with a metal, such as titanium,
niobium, cobalt, tantalum, nickel, iron or combinations thereof,
which may adhere better to the particles to the matrix. The
particles may be bonded by melting the matrix material to a
temperature sufficient to melt the matrix but still below the
melting temperature of the steel. A metal bonded matrix may
comprise a melting temperature from 700 to 1200 degrees Celsius. A
heat sink may be placed over at least part of the superhard
material 207 or other part of the pick 101 during the heating
stage. Water or other fluid may be circulated around the heat sink
to remove the heat. The heat sink may also be used to apply a force
on the pick 101 to hold it together while brazing.
In some embodiments of the invention the composite material 1001
may comprise resin bonded particles. These particles may be bonded
by a resin selected from the group consisting of polyepoxides,
plastics, thermosetting resins, epoxies, polymers, epichlorohydrin,
bisphenol A, polyimide, and combinations thereof. The resin may be
hardened by adding an activating compound, thereby inducing a
chemical reaction, such as a polymerization reaction.
Picks 101 may be used in various applications. The pick 101 may be
disposed in an asphalt milling machine 103, as in the embodiment of
FIG. 1. FIGS. 11 through 14 disclose various wear applications that
may be incorporated with the present invention. FIG. 11 discloses a
drill bit 1110 typically used in water well drilling. FIG. 12
discloses a drill bit 1120 typically used in subterranean,
horizontal drilling. These bits 1110, 1120, and other bits, may be
consistent with the present invention. The pick 101 may be used in
a trenching machine, as disclosed in FIGS. 13 through 14. Picks 101
may be disposed on a rock wheel trenching machine 1301 as disclosed
in FIG. 13. Referring to FIG. 14, the picks 101 may be placed on a
chain that rotates around an arm 1402 of a chain trenching machine
1401. Other applications that involve intense wear of machinery may
also be benefited by incorporation of the present invention.
Milling machines, for example, may experience wear as they are used
to reduce the size of material such as rocks, grain, trash, natural
resources, chalk, wood, tires, metal, cars, tables, couches, coal,
minerals, chemicals, or other natural resources. Various mills that
may incorporate the composite material include mulchers, vertical
shaft mills, hammermills, cone crushers, chisels, jaw crushers, or
combinations thereof. Percussion bits, roller cone bits, and shear
bits used in the oil and gas industry may also incorporate the
composite material.
Referring now to FIG. 15, a method 1500 of providing a cost
effective pick is disclosed in the form of a flowchart. The method
1500 comprises a step 1501 of providing a pick 101 adapted for
attachment to a driving mechanism. The driving mechanism may be a
milling drum connected to a pavement milling machine. The pick 101
comprises a shank 202 and a used cemented metal carbide core 204
attached to a worn steel body 201. The carbide core 204 may be
press fit to a depth 304 of at least 65% of a length 210 of the
worn or unused steel body 201. The carbide core 204 may be press
fit to a depth of the steel body such that a distance 303 from the
shank 202 to the second end 301 of the carbide core 204 is less
than the diameter 302 of the core 204. The carbide core 204
comprises a superhard material 207 on an impact surface
substantially opposite the shank. In some embodiments of the
invention step 1501 may comprise retrieving a rented pick from a
second party. The method 1500 further comprises a step 1502 of
removing the used carbide core 204 from the worn steel body 201.
The carbide core 204 may be removed by cutting or grinding away
portions of the steel body 201 of the provided pick 101. The method
1500 further comprises a step 1503 of press fitting the used
carbide core 204 into a cavity 404 substantially opposite a shank
of a substantially unused steel body 201 of a pick 101.
The shank 202 may be adapted to be secured to a bit body adapted
for subterranean drilling, or to a trenching machine. In some
embodiments of the invention a wear resistant washer 209 may be
disposed around the shank 202 proximate the steel body 201. In some
embodiments of the invention the method 1500 may comprise a step of
selling the pick 101 with an incentive given for eventual return of
the used core 204 or body 201.
Referring row to FIG. 16, a method 1600 of providing a cost
effective pick 101 is disclosed in the form of a flowchart. The
method 1600 comprises steps 1501, 1502 and 1503 as detailed in the
description of FIG. 15. The method 1600 further comprises a step
1601 of renting the pick 101 to a second party for use according to
a rental agreement and a step 1602 of retrieving the rented pick
from the second party according to the terms of the agreement. The
second party may be charged for the amount of time that they
possess or use the pick 101, for the volume, weight, area, or
amount of material milled with the pick 101, or for the distance or
area of material milled with the pick 101. In some embodiments of
the invention the second party may be charged for the profit or
revenue generated with the picks 101.
Whereas the present invention has been described in particular
relation to the drawings attached hereto, it should be understood
that other and further modifications apart from those shown or
suggested herein, may be made within the scope and spirit of the
present invention.
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